1. Field of the Invention
The present invention relates generally to golf clubs, and more particularly, to a golf putter having positively locked striking surface attachments, and a method for replacing such striking surface attachments.
2. Background of the Invention
Most golfers recognize that putting with accurate direction and distance requires a club that communicates a precise sense of touch and feel. The desire to maximize this precise touch and feel and to accurately control the direction of the ball has spawned literally hundreds of golf putter designs. Examples of these various designs include increased putter head mass to accommodate short backswings and lengthen ball travel, balanced putter head mass to improve directional accuracy, decreased putter head mass to increase accuracy, and special putter face striking surfaces that impart a heightened sense of feel and touch in controlling the rebound characteristics of the ball. This last aspect, concerning putter face striking surfaces, is the subject of the present application.
Golfers typically favor customized golf clubs that enhance, improve, or correct their particular style of play. For manufacturers, this customizing presents a significant challenge, especially when attempting to sell golf clubs to the mass market at competitive prices. With putters, manufacturers have experimented extensively with offering varieties of putter striking surfaces to accommodate personal preferences for club feel and touch. Thus far, manufacturers have offered two principal ways to purchase customized golf putters: 1) one-time customization, in which the manufacturer typically offers a full line of putters with basic designs, but with a variety of striking surfaces designed to appeal to diverse tastes; and 2) adjustable customization, in which a manufacturer typically offers a multi-component putter with a putter head that accepts a variety of interchangeable striking surface attachments, each suitable for different playing styles or playing conditions. The ultimate goal of each of these customization methods is to give the golfer a specialized feel and control that will persuade the golfer to purchase the customized putter instead of a non-customized putter.
In addition to appealing to golfers' desire for customized clubs, some putters attempt to conform to United States Golf Association (USGA) rules to be acceptable for USGA sanctioned play. For customized putters featuring varying striking surfaces or varying attachments, manufacturers desiring USGA conformance must pay particular attention to the USGA rules concerning the attachment of club components and the adjustability of clubs. Specifically, Appendix II.1.a of the USGA rules states that “all parts of the club shall be fixed so that the club is one unit, and it shall have no external attachments except as otherwise permitted by the Rules.” Concerning adjustability, Appendix II.1.b.ii of the USGA rules, adopted to accommodate multi-component putters, states that all methods of adjustment require that “all adjustable parts are firmly fixed and there is no reasonable likelihood of them working loose during a round.” For one-time customized putters, these rules are typically no obstacle because construction of the club is completed and fixed at the factory, i.e., the club has a fixed face. For adjustable customized putters, however, the multi-components sometimes are not firmly fixed nor positively locked and can have a tendency to work loose and/or fail to deliver the feel and performance of firmly fixed components.
Turning to examples of the two types of customized putters, U.S. Pat. No. 5,458,332 to Fisher and U.S. Pat. No. 5,531,439 to Azzarella disclose one-time customized fixed-face golf putter heads having recesses into which inserts are wedged and permanently fitted. In addition, U.S. Pat. No. 5,674,132 to Fisher also discloses an insert wedged into the recess of a golf putter head, but also adds an adhesive layer that securely holds the wedge insert within the recess. In adding this adhesive layer, U.S. Pat. No. 5,674,132 teaches that the adhesive helps to avoid the loosening of the insert by repeated contact of the insert bottom with the ground, during normal usage of the club. However, these one-time customized striking surface putters do not accommodate the desire to fine-tune his putter or to quickly change striking surfaces for varied playing conditions. In other words, if a striking surface is attached to a putter head by a wedged, permanent fit or a wedged fit with adhesive, the striking surface is not quickly removable.
To address this desire to repeatedly change striking surfaces, the adjustable customization designs incorporate multi-component putter heads with replaceable parts, e.g., striking surface inserts or striking surface attachments. Applicant's U.S. Pat. No. 5,332,214 discloses a golf putter that includes a multi-component head having an elastomeric striking surface, a support member for the elastomeric striking surface, a weight, a body member, and screws. The body member includes a recessed area extending substantially across the front of the body member, a central cavity extending through the body member for receiving the weight, and holes through the body member for receiving the screws. The support member includes holes for receiving the screws when the support member is fitted into the recessed area. The elastomeric striking surface is cast or adhesively secured to the support member, together making a striking surface insert.
Similarly, U.S. Pat. No. 4,121,832 to Ebbing, U.S. Pat. No. 5,690,562 to Sturm, U.S. Pat. No. 5,746,664 to Reynolds, Jr., U.S. Pat. No. 5,839,974 to McAllister, and U.S. Pat. No. 5,921,871 to Fisher all disclose golf putters having an insert fastened to a putter head using threaded screws. Each of these designs uses screws to firmly fix and positively secure the components of the putter head in a manner similar to that taught by applicant's U.S. Pat. No. 5,332,214 and determined by the USGA to be in conformance with its rules. Unfortunately, this use of screws complicates adjusting of the club by requiring tools and frustrates the golfer's ability to quickly fine-tune his putter or to easily adapt the club for varying playing conditions. In the end, golfers typically make a one-time adjustment after the purchase of the club and forgo attempts to customize the club before playing. Thus, if a striking surface is attached to a putter head using a screw, the striking surface is not quickly removable.
In an attempt to simplify adjustable customization, other types of removable insert golf putters teach interference fits in lieu of screws. However, in each case the fit is either poorly secured or secured so tightly that further adjustment is impossible. As an example of a poorly secured fit, U.S. Pat. No. 5,542,675 to Micciche et al. discloses an adaptor that snaps onto the putter head, providing an elastomeric striking surface for the putter head. Micciche explains that the putter head adaptor is “adapted to engage” around the putter head, but fails to disclose how the adaptor engages the putter head or how loose or rattling fits, caused by variances in manufacturing such as shrinkage and inconsistent dimensions, are avoided. U.S. Pat. No. 5,620,381 to Spalding discloses a removable putting face insert having a resilient rear wedge portion that is sized and positioned to press fit within a recess of the putter head. However, Spalding specifically teaches that the press fit arrangement is tight enough such that alteration of the club by a golfer is virtually impossible. U.S. Pat. No. 5,718,644 to Donofrio discloses a putter head that can retain an insert by frictional fit. However, Donofrio specifically contemplates that the insert is permanently attached and impossible to remove, and actually prefers the use of high strength epoxy for the permanent attachment, or alternatively, welding, brazing, bolts, screws, integral latches, or other mechanical fasteners. Thus, if a striking surface is attached to a putter head using high strength epoxy, welding, brazing, bolts, screws, or integral latches as a permanent attachment, the striking surface is not quickly removable.
In another attempt at adjustable customization, U.S. Pat. Nos. 5,690,561 and 5,688,190 to Rowland et al. disclose the removable application of textured adhesive backed pads to a club face. However, the use of temporary adhesive will over time fail to provide a positive lock as the effectiveness of the adhesive deteriorates with use.
Thus, conventional adjustable customized golf putters fail to satisfy golfers' preferences for easily customizing or fine-tuning the putter to adapt to changing playing styles or changing playing conditions. Putters fastened with screws or similar fasteners can require tools and can prolong replacement of the striking surface insert such that a golfer experimenting with different inserts loses the unique feel of the prior inserts. In short, the striking surface inserts of these types of putters are not quickly removable. In addition, the golfer can lose the screws or similar fasteners, making the club useless.
Although simplifying adjustment, the conventional adjustable customized putters that use interference fits or temporary adhesive also fail to positively secure the insert. The interference fits fail, in part, due to the many variables in manufacturing, including shrinkage and process variations that contribute to inconsistent shapes and dimensions. The consequence of this inconsistency is an undesirable looseness. Likewise, the temporary adhesives do not provide a positive lock and, in addition, deteriorate over time.
As used herein, “looseness” is defined by any independent movement of a club component perceptible to a golfer while using the club to strike a ball. Perceptible includes feeling or hearing independent movement. For example, feeling or hearing a rattle is indicative of looseness. Looseness in a putter prevents replication of the feel of a fixed face putter, and prevents even acceptable performance of the putter.